Green vat dyestuffs and process of making same.



UNITED STATES PATENT ornion.

. BERTRAM MAYER, OF BASEL, SWITZERLAND, A SSIGNOB, T SOCIETY OF CHEMICAL INDUSTRY IN BASLE, OF BASEL, SWITZERLAND.

GREEN VAT DYESTUFFS AND PROCESS OF MAKING No Drawing.

Specification of Letters Patent. Application filed June 3, 1913. Serial No. 771,535.

' Patented May is, 1914.

stuffs and a Process of Making Same, of

which the following is a full, clear, and exact specification.

I have found, that the sulfureted vat dyestuif derived from 2-methylbenzanthrone and described in the U. S. Letters Patent No. 1044797 and No. 927868 can be transformed by its treatment with nitric acid into precious dyestuffs dyeing textile fibers from an alkaline vat pure green to olive tints, while the sulfureted vat dyestuif employed as parent material dyes textile fibers from an alkaline vat bluish green tints.

The following-examples illustrate the invention: y

Example I: 100 parts of the sulfureted vat dyestuff derived from Q-methylbenzanthrone are dissolved in 4000 parts of sulfuric acid of 94 per cent; in the solution thus obtained are poured slowly, at the ordinary tempera-- ture, 195 parts of a mixture of sulfuric acid and of nitric acid, of 6%, care being taken to stir the solution continually. The mass is further stirred for a certain time and poured afterward on ice and filtered. The paste thus obtained is employed directly for dyelng purposes. In a dry state, the new dyestuif is a dark powder of metallic luster, insoluble in the usual solvents as alcohol, toluene and glacial acetic acid, and dissolving very ditticultly in boiling nitrobenzene with a green coloration. In concentrated sulfuric acid and in fuming sulfuric acid it dissolves to solutions of violetish brown to dirty-violet coloration. By heating the dyestuff with an alkaline solution of hydrosulfite a blue vat is obtained from which cotton is dyed verypure and fast. green tints.

' Example 11: 100 parts of the sulfureted vat dyestufs' derived fromQ-methylbenzanthrone are stirred together with 2000 parts of nitrobenzene and 5 parts of concentrated nitric acid for about 5 hours at the ordinary temperature. The reaction mass is hereafter diluted with alcohol, the dyestufi' thus separated dried by suction and washed with alcohol. The product thus obtained constitutes a powder of coppery luster, which dissolves very difiicultly in boiling nitrobenzene with a green coloration. It dissolves in concentrated sulfuric acid to a brown-red solution and in fuming sulfuric acid to a dirty-violet solution with an alkaline so lution of hydrosulfite the dyestulf yields a pure blue vat from which cotton is dyed fast olive tints.

What I claim is:

1. The described process for the manufacture of green vat dyestuffs, consisting in treating the known green-blue sulfureted vat dycstufi' derived from Q-methylbenzanthrone with nitric acid,

2. As new products, the described green Zreted vat dyestuif derived from 2 methylbenzanthrone, which constitute in dry state dark powders of metallic luster, are insoluble in the usual solvents as alcohol, toluene and glacial acetic acid, dissolve very ditlicultly in boiling nitrobenzene to green solu tions, dissolve in concentrated sulfuric acid and 1n fuming sulfuric acld to solutions of brown to dirtyviolet coloration and yield with alkaline reducing agents a pure blue vat from which textile fibers are dyed fast green to olive tints.

In witness whereof I have hereunto signed my name this 22d day of May, 1913, in the presence of two subscribing witnesses.

BERTRAM MAYER.

Witnesses Geo. Grrrono, AMAND 312mm. 

